Recently, an image projecting device called an “ultra-short focus projector” has been commercialized. The ultra-short focus projector has the same projector screen size as conventional projectors but requires a shorter length to a projector surface (i.e., a screen). Since the distance to the projector surface is shorter, there are the following merits.    1. A space can be effectively utilized.    2. Projected light does not easily impinge on a presenter, and thus glare is reduced and a ghost image is prevented.    3. A distance between the image projecting device and a viewer is made greater, and thus heat and noise from the image projecting device is not annoying.
In order to make these merits more effective, it is preferred that the image projecting device has a vertical configuration so that a footprint is reduced and the image projecting device can be placed closer to a wall.
However, if the image projecting device has a vertical configuration, it can topple easily. If the image projecting device topples, the projected light may be shown into the eyes of the viewer and cause glare. Further, if the toppled image projecting device is left for a long time, a cooling mechanism does not work sufficiently, which increases the temperature of the image projecting device and causes internal parts to fail. For this reason, there is a technique for automatically stopping the projection if toppling of the image projecting device is detected.
Japanese Laid-open Patent Publication No. 2008-009136 discloses an image projection device for projecting an image which device projects a plurality of images in a plurality of directions around an image projection device main body nearly on the same surface as the installation surface of the image projection device, for the purpose of providing an image projection device readily installed on a table in a conference or the like and projecting an image in front of all the persons present, thereby progressing an argument. This image projecting device includes an inertia sensor as a detecting part for detecting the toppling, and turns off the power supply of a light source to stop the output when the toppling of the image projecting device is detected.
As described above, according to the image projecting device of the prior art which forcefully stops the projection when the toppling of the image projecting device is detected, there is a problem that it takes time to resume the projection after the image projecting device is restored to the original position. This is because it takes a certain time for an ordinary image projecting device to restart the projection once the projection is stopped.
The present invention is made in consideration of the problem of the prior art described above, and an object of the present invention is to provide an image projecting device with increased convenience by minimizing stoppage of the image projection at the time of toppling of the image projecting device.